• 한국환경과학회지
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• 제20권6호
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• pp.687-700
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• 2011

A new $N_3-O_2$ pentadentate ligand, H-BHPT, was synthesized. Hydrochloric acid salts of Br-BHPT, Cl-BHPT, $CH_3O$-BHPT and $CH_3$-BHPT, having Br-, Cl-, $CH_{3-}$ and $CH_3O-$ substituents at the para position of the phenol hydroxyl group of H-BHPT were synthesized. Hydrochloric acid salts of 3OH-BHPT and 4OH-BHPT, having different position of the phenol hydroxyl group of H-BHPT were also synthesized. The synthesis of each ligand was confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible, and mass spectra. The calculated proton dissociation constants ($log{K_n}^H$) of the phenol hydroxyl group and secondary amine group of the synthesized $N_3-O_2$ ligands showed five steps of the proton dissociations. The order of the overall proton dissociation constants ($log{\beta}_p$) of the ligands was Br-BHPT < Cl-BHPT < H-BHPT < $CH_3O$-BHPT < $CH_3$-BHPT. The order agreed with that of Hammett substituent constants (${\delta}_p$). However, dissociation steps of 3OH-BHPT were four and that of 4OH-BHPT was three. The calculated stability constants ($logK_{ML}$) between the ligands and transition metal ions agreed with the order of $log{\beta}_p$ values of the ligands. The order of the stability constants between the transition metal ions with the synthesized ligands was Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II). The order agreed well with that of the Iriving-Williams.

• 공업화학
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• 제28권3호
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• pp.294-298
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• 2017

Dimethyl terephthalate (DMT) 생산과정의 부산물로서 폐기 처리되어왔던 methyl 4-formylbenzoate (MFB)를 출발 물질로하여 고급 형광증백제 family인 Uvitex FP와 동일한 4,4'-di((E)-styryl)-1,1'-biphenyl 기본 골격을 갖는 새로운 형광증백제(fluorescent whitening agent) 후보 물질 6종을 합성하였다. 후보 물질 6종은 MFB 및 그의 유도체와 tetraethyl biphenyl-4,4'-diylbis(methylene) diphosphonate (3)와 Wittig-Horner 반응을 이용하여 합성하였다. 합성된 6종에 대하여 형광증백제로의 가능성을 확인하기 위하여 UV spectrum을 기록하여 몰흡광 계수를 얻었으며, 6종 모두 Uvitex FP 127(log ${\varepsilon}$ 4.85)보다 낮은 몰흡광 계수(log ${\varepsilon}$ 3.95~2.60)를 보임으로서 형광증백제로는 적합하지 못한 것을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.297-300
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• 2007

In this study, we have attempted a new method to enhance the coloring of dye on the $TiO_2$ surface in the dye sensitized solar cell. In the conventional coloring process in a dye sensitized solar cells, dye is absorbed by the covalent bond between TiO2 and dye molecule while the photo-electrode coated with $TiO_2$ layer is soaked in dye solution for about 12-24 hours. But this process takes long time, so we have researched more effective and faster way than the conventional process by applying electric field. Three kinds of electric power such as direct voltage, alternating voltage and pulse voltage were applied to the transparent conducting oxide during the coloring process. As a result, we achieved improved power, fill factor and efficiency of dye-sensitized solar cell in case of applying direct voltage and pulse voltage. In contrast, alternating voltage tend to reduce the dye adsorption on the $TiO_2$ surface and hence the efficiency. We measured the absorption spectra of dye by UV-VIS spectrophotometer before and after soaking the $TiO_2$ in the dye and found no characteristic change in the dye was observed. In this study, we researched on shortening time of coloring process which spent much time in the whole process.

• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.186-192
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• 2013

In order to reduce the costs and to improve the durability of solid oxide fuel cell (SOFC), the operating temperature should be decreased while the power density is maintained as much as possible. However, lowering the operating temperature increases the cathode interfacial polarization resistances dramatically, limiting the performance of low-temperature SOFC at especially purely electronic conducting cathode. To improve cathode performance at low temperature, the number of reaction sites for the oxygen reduction should be increased by using a mixed ionic and electronic conducting (MIEC) material. In this study, anode-supported fuel cells with two different thicknesses of the MIEC cathode were fabricated and tested at various operating temperatures. The anode supported cell with $32.5{\mu}m$-thick BSCFZn-LSCF cathode layer showed much lower polarization resistance than that with $3.2{\mu}m$ thick cahtode and higher power density especially at low temperature. The effects of cathode layer thickness on the electrochemical performance are discussed with analysis of impedance spectra.

• 멤브레인
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• 제29권6호
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• pp.323-328
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• 2019

인류의 에너지 수급은 항상 인간의 삶에 중요한 문제이며, 최근에는 전기 생산 및 공급 문제로 이어지고 있다. 이에 관련하여 본 연구에서는 에너지 저장장치의 일환으로 슈퍼커패시터 용도의 고체 전해질막을 제조하였다. 제조한 전해질막은 poly(vinyl alcohol) (PVA) 주사슬에 poly(oxyethylene methacrylate) (POEM) 곁사슬을 그래프팅하여 사용하였으며, 그래프팅은 자유 라디칼 중합법을 통해 합성하였다. 본 연구에서 사용한 PVA-g-POEM 가지형 공중합체를 슈퍼커패시터 전해질에 적용한 사례는 처음이다. POEM 그래프팅을 통해 PVA가 고유하게 가지고 있던 구조가 변화하였으며, 이를 FT-IR을 통해 분석하였다. 또한, 합성한 공중합체를 이용한 슈퍼커패시터 성능은 cyclic voltammetry (CV), galvanostatic charge/discharge(GCD), ragone plot 등을 통해 분석하였다. 이를 통해 기존에 수계 전해질로 PVA 단일 고분자만 사용하던 분야에 그래프팅 방법이라는 새로운 접근법을 제시하였다.

• 대한화학회지
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• 제33권5호
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• pp.510-515
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• 1989

테트라에틸렌펜타아민과 포름알데히드의 주형축합반응으로부터 새로운 펜타아자 거대두고리 리간드인 1,3,6,9,12-펜타아자비시클로[10,2,1]펜타데칸(D)의 니켈(II) 및 구리(II) 착화합물 $[Ni(D)]^{2+},\;[Cu(d)]6{2+}\;그리고\;[Cu(D)Cl]^+$를 합성하였다. 거대두고리 리간드인 D에는 한 개의 이미다졸리딘 고리가 있다. $[Ni(D)]^{2+}와 [Cu(D)]^{2+}$는 5-5-5-6 킬레이트고리 배열로 된 평면사각형 구조를 이루며, 5-배위 착이온인 $[Cu(D)Cl]^+$의 구조는 그의 전자스펙트럼으로 볼 때 사각피라미드일 것으로 보인다. 이들 니켈(II) 및 구리(II) 착화합물의 합성과 확인 그리고 분광학적인 특성과 화학적인 특성이 논의된다.

• 대한화학회지
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• 제38권7호
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• pp.485-495
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• 1994

$[M(NO)_2Cl_2]_n(M = Mo, W)$을 출발물질로 사용하여 3단계 합성과정을 거쳐 $[Cl(dppp)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$와 $[Cl(phen)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$(M,M'= Mo or W; phen = 1,10-phenanthroline; dppp = 1,3-bis(diphenylphosphino)propane; pyz = 1,4-pyrazine) 형의 새로운 대칭 및 비대칭 이핵 착물을 합성하였다. 최종 생성물은 실리카겔 칼럼($2{\times}20$ cm)을 통해 아세톤으로 용리시켜 분리하였다. 합성한 착물은 원소분석과 적외선, 핵사기 공명 및 전자 흡수스펙트럼 등을 이용해서 그 특성을 조사하였다. 적외선 스펙트럼은 모든 착물이 팔면체 구조로서 두 개의 NO기가 cis 위치로 배위되어 있음을 나타냈으며, $^1H$ 및 $^{13}C$ 핵자기 공명 스펙트럼은 이들 착물이 pyz가 다리결합하고 있는 이핵 착물임을 나타내었다.

• 한국환경과학회지
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• 제19권7호
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• pp.849-860
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• 2010

A new $N_3O_2$ pentadentate ligand, N,N'-Bis(2-hydroxybenzyl)-ethylenetriamine(H-BHET 3HCl) was synthesized. The hydrochloric acid salts of Br-BHET 3HCl, Cl-BHET 3HCl, $CH_3O$-BHET 3HCl and $CH_3$-BHET 3HCl containing Br-, Cl-, H-, $CH_3O-$ and $CH_3-$ groups at the para-site of the phenol group of the H-BHEP were synthesized. The structures of the ligands were confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible and mass spectra. The calculated stepwise protonation constants(${\logK_n}^H$) of the synthesized $N_3O_2$ ligands showed six steps of the proton dissociation. The orders of the overall protonation constants($\log{\beta}_p$) of the ligands were Br-BHET < Cl-BHET < H-BHET < $CH_3O$-BHET < $CH_3$-BHET. The orders agreed well with that of para Hammett substituent constants(${\delta}_p$). The calculated stability constants($\logK_{ML}$) between the ligands and heavy metal ions (Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II)) agreed well with the order of the overall proton dissociation constants of the ligands but they showed a reverse order in para Hammestt substituent constants(${\delta}_p$). The order of the stability constants between the heavy metal ions with the synthesized ligands were Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II).

• 천문학회보
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• 제39권1호
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• pp.51.1-51.1
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• 2014

DOTIFS is a new multi-object Integral Field Spectrograph (IFS) being designed and fabricated by the Inter-University Center for Astronomy and Astrophysics, Pune, India, (IUCAA) for the Cassegrain side port of the 3.6m Devasthal Optical Telescope (DOT). The telescope is constructed by the Aryabhatta Research Institute of Observational Sciences, Nainital (ARIES). Its main scientific objectives are the physics and kinematics of the ionized gas, star formation and H II regions in nearby galaxies. It is a novel instrument in terms of multi-IFU, built in deployment system, and high throughput. It consists of one magnifier, 16 integral field units (IFUs), and 8 spectrographs. Each IFU is comprised of a microlens array and 144 optical fibers, and has $7.4^{\prime\prime}{\times}8.7^{\prime\prime}$ field of view with 144 spaxel elements with a sampling of 0.8" hexagonal aperture. The IFUs can be deployed on the telescope side port over an 8' diameter focal plane by x-y actuators. 8 Identical, all refractive, dedicated fiber spectrographs will produce 2,304 R~1800 spectra over 370-740nm wavelength range with single exposure. Currently, conceptual and baseline design review had been done, and is in the critical design phase with a review planned for later this year. Some of the components have already arrived. The instrument will see its first light in 2015.

• 한국수소및신에너지학회논문집
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• 제29권3호
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• pp.260-266
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• 2018

To enhance catalyst activity of the palladium (Pd) towards oxygen reduction reaction (ORR), iridium (Ir) and yttrium (Y) were alloyed by polyol method. Due to the low reduction potential of Y, it is hard to reduce Y ion completely by polyol method. In XPS spectra, the binding energy of the Pd is shifted to a lower value, which indicates the d-electron of Pd is filled by the electron from the Y. And other phases of Y are observed by the XPS. Among the catalysts, the $Pd_4IrY_{0.1}/C$ showed the best activity towards ORR, which indicates the metallic Y is effective for improving the catalytic activity. Thus, for further enhancing ORR activity, the novel method for complete reduction of Y is needed.